linux/drivers/net/xen-netfront.c
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   1/*
   2 * Virtual network driver for conversing with remote driver backends.
   3 *
   4 * Copyright (c) 2002-2005, K A Fraser
   5 * Copyright (c) 2005, XenSource Ltd
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public License version 2
   9 * as published by the Free Software Foundation; or, when distributed
  10 * separately from the Linux kernel or incorporated into other
  11 * software packages, subject to the following license:
  12 *
  13 * Permission is hereby granted, free of charge, to any person obtaining a copy
  14 * of this source file (the "Software"), to deal in the Software without
  15 * restriction, including without limitation the rights to use, copy, modify,
  16 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  17 * and to permit persons to whom the Software is furnished to do so, subject to
  18 * the following conditions:
  19 *
  20 * The above copyright notice and this permission notice shall be included in
  21 * all copies or substantial portions of the Software.
  22 *
  23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  25 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  26 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  27 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  28 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  29 * IN THE SOFTWARE.
  30 */
  31
  32#include <linux/module.h>
  33#include <linux/kernel.h>
  34#include <linux/netdevice.h>
  35#include <linux/etherdevice.h>
  36#include <linux/skbuff.h>
  37#include <linux/ethtool.h>
  38#include <linux/if_ether.h>
  39#include <linux/tcp.h>
  40#include <linux/udp.h>
  41#include <linux/moduleparam.h>
  42#include <linux/mm.h>
  43#include <linux/slab.h>
  44#include <net/ip.h>
  45
  46#include <asm/xen/page.h>
  47#include <xen/xen.h>
  48#include <xen/xenbus.h>
  49#include <xen/events.h>
  50#include <xen/page.h>
  51#include <xen/platform_pci.h>
  52#include <xen/grant_table.h>
  53
  54#include <xen/interface/io/netif.h>
  55#include <xen/interface/memory.h>
  56#include <xen/interface/grant_table.h>
  57
  58static const struct ethtool_ops xennet_ethtool_ops;
  59
  60struct netfront_cb {
  61        int pull_to;
  62};
  63
  64#define NETFRONT_SKB_CB(skb)    ((struct netfront_cb *)((skb)->cb))
  65
  66#define RX_COPY_THRESHOLD 256
  67
  68#define GRANT_INVALID_REF       0
  69
  70#define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
  71#define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
  72#define TX_MAX_TARGET min_t(int, NET_TX_RING_SIZE, 256)
  73
  74struct netfront_stats {
  75        u64                     rx_packets;
  76        u64                     tx_packets;
  77        u64                     rx_bytes;
  78        u64                     tx_bytes;
  79        struct u64_stats_sync   syncp;
  80};
  81
  82struct netfront_info {
  83        struct list_head list;
  84        struct net_device *netdev;
  85
  86        struct napi_struct napi;
  87
  88        unsigned int evtchn;
  89        struct xenbus_device *xbdev;
  90
  91        spinlock_t   tx_lock;
  92        struct xen_netif_tx_front_ring tx;
  93        int tx_ring_ref;
  94
  95        /*
  96         * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
  97         * are linked from tx_skb_freelist through skb_entry.link.
  98         *
  99         *  NB. Freelist index entries are always going to be less than
 100         *  PAGE_OFFSET, whereas pointers to skbs will always be equal or
 101         *  greater than PAGE_OFFSET: we use this property to distinguish
 102         *  them.
 103         */
 104        union skb_entry {
 105                struct sk_buff *skb;
 106                unsigned long link;
 107        } tx_skbs[NET_TX_RING_SIZE];
 108        grant_ref_t gref_tx_head;
 109        grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
 110        unsigned tx_skb_freelist;
 111
 112        spinlock_t   rx_lock ____cacheline_aligned_in_smp;
 113        struct xen_netif_rx_front_ring rx;
 114        int rx_ring_ref;
 115
 116        /* Receive-ring batched refills. */
 117#define RX_MIN_TARGET 8
 118#define RX_DFL_MIN_TARGET 64
 119#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
 120        unsigned rx_min_target, rx_max_target, rx_target;
 121        struct sk_buff_head rx_batch;
 122
 123        struct timer_list rx_refill_timer;
 124
 125        struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
 126        grant_ref_t gref_rx_head;
 127        grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
 128
 129        unsigned long rx_pfn_array[NET_RX_RING_SIZE];
 130        struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1];
 131        struct mmu_update rx_mmu[NET_RX_RING_SIZE];
 132
 133        /* Statistics */
 134        struct netfront_stats __percpu *stats;
 135
 136        unsigned long rx_gso_checksum_fixup;
 137};
 138
 139struct netfront_rx_info {
 140        struct xen_netif_rx_response rx;
 141        struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
 142};
 143
 144static void skb_entry_set_link(union skb_entry *list, unsigned short id)
 145{
 146        list->link = id;
 147}
 148
 149static int skb_entry_is_link(const union skb_entry *list)
 150{
 151        BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
 152        return (unsigned long)list->skb < PAGE_OFFSET;
 153}
 154
 155/*
 156 * Access macros for acquiring freeing slots in tx_skbs[].
 157 */
 158
 159static void add_id_to_freelist(unsigned *head, union skb_entry *list,
 160                               unsigned short id)
 161{
 162        skb_entry_set_link(&list[id], *head);
 163        *head = id;
 164}
 165
 166static unsigned short get_id_from_freelist(unsigned *head,
 167                                           union skb_entry *list)
 168{
 169        unsigned int id = *head;
 170        *head = list[id].link;
 171        return id;
 172}
 173
 174static int xennet_rxidx(RING_IDX idx)
 175{
 176        return idx & (NET_RX_RING_SIZE - 1);
 177}
 178
 179static struct sk_buff *xennet_get_rx_skb(struct netfront_info *np,
 180                                         RING_IDX ri)
 181{
 182        int i = xennet_rxidx(ri);
 183        struct sk_buff *skb = np->rx_skbs[i];
 184        np->rx_skbs[i] = NULL;
 185        return skb;
 186}
 187
 188static grant_ref_t xennet_get_rx_ref(struct netfront_info *np,
 189                                            RING_IDX ri)
 190{
 191        int i = xennet_rxidx(ri);
 192        grant_ref_t ref = np->grant_rx_ref[i];
 193        np->grant_rx_ref[i] = GRANT_INVALID_REF;
 194        return ref;
 195}
 196
 197#ifdef CONFIG_SYSFS
 198static int xennet_sysfs_addif(struct net_device *netdev);
 199static void xennet_sysfs_delif(struct net_device *netdev);
 200#else /* !CONFIG_SYSFS */
 201#define xennet_sysfs_addif(dev) (0)
 202#define xennet_sysfs_delif(dev) do { } while (0)
 203#endif
 204
 205static bool xennet_can_sg(struct net_device *dev)
 206{
 207        return dev->features & NETIF_F_SG;
 208}
 209
 210
 211static void rx_refill_timeout(unsigned long data)
 212{
 213        struct net_device *dev = (struct net_device *)data;
 214        struct netfront_info *np = netdev_priv(dev);
 215        napi_schedule(&np->napi);
 216}
 217
 218static int netfront_tx_slot_available(struct netfront_info *np)
 219{
 220        return (np->tx.req_prod_pvt - np->tx.rsp_cons) <
 221                (TX_MAX_TARGET - MAX_SKB_FRAGS - 2);
 222}
 223
 224static void xennet_maybe_wake_tx(struct net_device *dev)
 225{
 226        struct netfront_info *np = netdev_priv(dev);
 227
 228        if (unlikely(netif_queue_stopped(dev)) &&
 229            netfront_tx_slot_available(np) &&
 230            likely(netif_running(dev)))
 231                netif_wake_queue(dev);
 232}
 233
 234static void xennet_alloc_rx_buffers(struct net_device *dev)
 235{
 236        unsigned short id;
 237        struct netfront_info *np = netdev_priv(dev);
 238        struct sk_buff *skb;
 239        struct page *page;
 240        int i, batch_target, notify;
 241        RING_IDX req_prod = np->rx.req_prod_pvt;
 242        grant_ref_t ref;
 243        unsigned long pfn;
 244        void *vaddr;
 245        struct xen_netif_rx_request *req;
 246
 247        if (unlikely(!netif_carrier_ok(dev)))
 248                return;
 249
 250        /*
 251         * Allocate skbuffs greedily, even though we batch updates to the
 252         * receive ring. This creates a less bursty demand on the memory
 253         * allocator, so should reduce the chance of failed allocation requests
 254         * both for ourself and for other kernel subsystems.
 255         */
 256        batch_target = np->rx_target - (req_prod - np->rx.rsp_cons);
 257        for (i = skb_queue_len(&np->rx_batch); i < batch_target; i++) {
 258                skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD + NET_IP_ALIGN,
 259                                         GFP_ATOMIC | __GFP_NOWARN);
 260                if (unlikely(!skb))
 261                        goto no_skb;
 262
 263                /* Align ip header to a 16 bytes boundary */
 264                skb_reserve(skb, NET_IP_ALIGN);
 265
 266                page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 267                if (!page) {
 268                        kfree_skb(skb);
 269no_skb:
 270                        /* Any skbuffs queued for refill? Force them out. */
 271                        if (i != 0)
 272                                goto refill;
 273                        /* Could not allocate any skbuffs. Try again later. */
 274                        mod_timer(&np->rx_refill_timer,
 275                                  jiffies + (HZ/10));
 276                        break;
 277                }
 278
 279                __skb_fill_page_desc(skb, 0, page, 0, 0);
 280                skb_shinfo(skb)->nr_frags = 1;
 281                __skb_queue_tail(&np->rx_batch, skb);
 282        }
 283
 284        /* Is the batch large enough to be worthwhile? */
 285        if (i < (np->rx_target/2)) {
 286                if (req_prod > np->rx.sring->req_prod)
 287                        goto push;
 288                return;
 289        }
 290
 291        /* Adjust our fill target if we risked running out of buffers. */
 292        if (((req_prod - np->rx.sring->rsp_prod) < (np->rx_target / 4)) &&
 293            ((np->rx_target *= 2) > np->rx_max_target))
 294                np->rx_target = np->rx_max_target;
 295
 296 refill:
 297        for (i = 0; ; i++) {
 298                skb = __skb_dequeue(&np->rx_batch);
 299                if (skb == NULL)
 300                        break;
 301
 302                skb->dev = dev;
 303
 304                id = xennet_rxidx(req_prod + i);
 305
 306                BUG_ON(np->rx_skbs[id]);
 307                np->rx_skbs[id] = skb;
 308
 309                ref = gnttab_claim_grant_reference(&np->gref_rx_head);
 310                BUG_ON((signed short)ref < 0);
 311                np->grant_rx_ref[id] = ref;
 312
 313                pfn = page_to_pfn(skb_frag_page(&skb_shinfo(skb)->frags[0]));
 314                vaddr = page_address(skb_frag_page(&skb_shinfo(skb)->frags[0]));
 315
 316                req = RING_GET_REQUEST(&np->rx, req_prod + i);
 317                gnttab_grant_foreign_access_ref(ref,
 318                                                np->xbdev->otherend_id,
 319                                                pfn_to_mfn(pfn),
 320                                                0);
 321
 322                req->id = id;
 323                req->gref = ref;
 324        }
 325
 326        wmb();          /* barrier so backend seens requests */
 327
 328        /* Above is a suitable barrier to ensure backend will see requests. */
 329        np->rx.req_prod_pvt = req_prod + i;
 330 push:
 331        RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->rx, notify);
 332        if (notify)
 333                notify_remote_via_irq(np->netdev->irq);
 334}
 335
 336static int xennet_open(struct net_device *dev)
 337{
 338        struct netfront_info *np = netdev_priv(dev);
 339
 340        napi_enable(&np->napi);
 341
 342        spin_lock_bh(&np->rx_lock);
 343        if (netif_carrier_ok(dev)) {
 344                xennet_alloc_rx_buffers(dev);
 345                np->rx.sring->rsp_event = np->rx.rsp_cons + 1;
 346                if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
 347                        napi_schedule(&np->napi);
 348        }
 349        spin_unlock_bh(&np->rx_lock);
 350
 351        netif_start_queue(dev);
 352
 353        return 0;
 354}
 355
 356static void xennet_tx_buf_gc(struct net_device *dev)
 357{
 358        RING_IDX cons, prod;
 359        unsigned short id;
 360        struct netfront_info *np = netdev_priv(dev);
 361        struct sk_buff *skb;
 362
 363        BUG_ON(!netif_carrier_ok(dev));
 364
 365        do {
 366                prod = np->tx.sring->rsp_prod;
 367                rmb(); /* Ensure we see responses up to 'rp'. */
 368
 369                for (cons = np->tx.rsp_cons; cons != prod; cons++) {
 370                        struct xen_netif_tx_response *txrsp;
 371
 372                        txrsp = RING_GET_RESPONSE(&np->tx, cons);
 373                        if (txrsp->status == XEN_NETIF_RSP_NULL)
 374                                continue;
 375
 376                        id  = txrsp->id;
 377                        skb = np->tx_skbs[id].skb;
 378                        if (unlikely(gnttab_query_foreign_access(
 379                                np->grant_tx_ref[id]) != 0)) {
 380                                printk(KERN_ALERT "xennet_tx_buf_gc: warning "
 381                                       "-- grant still in use by backend "
 382                                       "domain.\n");
 383                                BUG();
 384                        }
 385                        gnttab_end_foreign_access_ref(
 386                                np->grant_tx_ref[id], GNTMAP_readonly);
 387                        gnttab_release_grant_reference(
 388                                &np->gref_tx_head, np->grant_tx_ref[id]);
 389                        np->grant_tx_ref[id] = GRANT_INVALID_REF;
 390                        add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, id);
 391                        dev_kfree_skb_irq(skb);
 392                }
 393
 394                np->tx.rsp_cons = prod;
 395
 396                /*
 397                 * Set a new event, then check for race with update of tx_cons.
 398                 * Note that it is essential to schedule a callback, no matter
 399                 * how few buffers are pending. Even if there is space in the
 400                 * transmit ring, higher layers may be blocked because too much
 401                 * data is outstanding: in such cases notification from Xen is
 402                 * likely to be the only kick that we'll get.
 403                 */
 404                np->tx.sring->rsp_event =
 405                        prod + ((np->tx.sring->req_prod - prod) >> 1) + 1;
 406                mb();           /* update shared area */
 407        } while ((cons == prod) && (prod != np->tx.sring->rsp_prod));
 408
 409        xennet_maybe_wake_tx(dev);
 410}
 411
 412static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
 413                              struct xen_netif_tx_request *tx)
 414{
 415        struct netfront_info *np = netdev_priv(dev);
 416        char *data = skb->data;
 417        unsigned long mfn;
 418        RING_IDX prod = np->tx.req_prod_pvt;
 419        int frags = skb_shinfo(skb)->nr_frags;
 420        unsigned int offset = offset_in_page(data);
 421        unsigned int len = skb_headlen(skb);
 422        unsigned int id;
 423        grant_ref_t ref;
 424        int i;
 425
 426        /* While the header overlaps a page boundary (including being
 427           larger than a page), split it it into page-sized chunks. */
 428        while (len > PAGE_SIZE - offset) {
 429                tx->size = PAGE_SIZE - offset;
 430                tx->flags |= XEN_NETTXF_more_data;
 431                len -= tx->size;
 432                data += tx->size;
 433                offset = 0;
 434
 435                id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
 436                np->tx_skbs[id].skb = skb_get(skb);
 437                tx = RING_GET_REQUEST(&np->tx, prod++);
 438                tx->id = id;
 439                ref = gnttab_claim_grant_reference(&np->gref_tx_head);
 440                BUG_ON((signed short)ref < 0);
 441
 442                mfn = virt_to_mfn(data);
 443                gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
 444                                                mfn, GNTMAP_readonly);
 445
 446                tx->gref = np->grant_tx_ref[id] = ref;
 447                tx->offset = offset;
 448                tx->size = len;
 449                tx->flags = 0;
 450        }
 451
 452        /* Grant backend access to each skb fragment page. */
 453        for (i = 0; i < frags; i++) {
 454                skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 455                struct page *page = skb_frag_page(frag);
 456
 457                len = skb_frag_size(frag);
 458                offset = frag->page_offset;
 459
 460                /* Data must not cross a page boundary. */
 461                BUG_ON(len + offset > PAGE_SIZE<<compound_order(page));
 462
 463                /* Skip unused frames from start of page */
 464                page += offset >> PAGE_SHIFT;
 465                offset &= ~PAGE_MASK;
 466
 467                while (len > 0) {
 468                        unsigned long bytes;
 469
 470                        BUG_ON(offset >= PAGE_SIZE);
 471
 472                        bytes = PAGE_SIZE - offset;
 473                        if (bytes > len)
 474                                bytes = len;
 475
 476                        tx->flags |= XEN_NETTXF_more_data;
 477
 478                        id = get_id_from_freelist(&np->tx_skb_freelist,
 479                                                  np->tx_skbs);
 480                        np->tx_skbs[id].skb = skb_get(skb);
 481                        tx = RING_GET_REQUEST(&np->tx, prod++);
 482                        tx->id = id;
 483                        ref = gnttab_claim_grant_reference(&np->gref_tx_head);
 484                        BUG_ON((signed short)ref < 0);
 485
 486                        mfn = pfn_to_mfn(page_to_pfn(page));
 487                        gnttab_grant_foreign_access_ref(ref,
 488                                                        np->xbdev->otherend_id,
 489                                                        mfn, GNTMAP_readonly);
 490
 491                        tx->gref = np->grant_tx_ref[id] = ref;
 492                        tx->offset = offset;
 493                        tx->size = bytes;
 494                        tx->flags = 0;
 495
 496                        offset += bytes;
 497                        len -= bytes;
 498
 499                        /* Next frame */
 500                        if (offset == PAGE_SIZE && len) {
 501                                BUG_ON(!PageCompound(page));
 502                                page++;
 503                                offset = 0;
 504                        }
 505                }
 506        }
 507
 508        np->tx.req_prod_pvt = prod;
 509}
 510
 511/*
 512 * Count how many ring slots are required to send the frags of this
 513 * skb. Each frag might be a compound page.
 514 */
 515static int xennet_count_skb_frag_slots(struct sk_buff *skb)
 516{
 517        int i, frags = skb_shinfo(skb)->nr_frags;
 518        int pages = 0;
 519
 520        for (i = 0; i < frags; i++) {
 521                skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 522                unsigned long size = skb_frag_size(frag);
 523                unsigned long offset = frag->page_offset;
 524
 525                /* Skip unused frames from start of page */
 526                offset &= ~PAGE_MASK;
 527
 528                pages += PFN_UP(offset + size);
 529        }
 530
 531        return pages;
 532}
 533
 534static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 535{
 536        unsigned short id;
 537        struct netfront_info *np = netdev_priv(dev);
 538        struct netfront_stats *stats = this_cpu_ptr(np->stats);
 539        struct xen_netif_tx_request *tx;
 540        struct xen_netif_extra_info *extra;
 541        char *data = skb->data;
 542        RING_IDX i;
 543        grant_ref_t ref;
 544        unsigned long mfn;
 545        int notify;
 546        int slots;
 547        unsigned int offset = offset_in_page(data);
 548        unsigned int len = skb_headlen(skb);
 549        unsigned long flags;
 550
 551        slots = DIV_ROUND_UP(offset + len, PAGE_SIZE) +
 552                xennet_count_skb_frag_slots(skb);
 553        if (unlikely(slots > MAX_SKB_FRAGS + 1)) {
 554                net_alert_ratelimited(
 555                        "xennet: skb rides the rocket: %d slots\n", slots);
 556                goto drop;
 557        }
 558
 559        spin_lock_irqsave(&np->tx_lock, flags);
 560
 561        if (unlikely(!netif_carrier_ok(dev) ||
 562                     (slots > 1 && !xennet_can_sg(dev)) ||
 563                     netif_needs_gso(skb, netif_skb_features(skb)))) {
 564                spin_unlock_irqrestore(&np->tx_lock, flags);
 565                goto drop;
 566        }
 567
 568        i = np->tx.req_prod_pvt;
 569
 570        id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
 571        np->tx_skbs[id].skb = skb;
 572
 573        tx = RING_GET_REQUEST(&np->tx, i);
 574
 575        tx->id   = id;
 576        ref = gnttab_claim_grant_reference(&np->gref_tx_head);
 577        BUG_ON((signed short)ref < 0);
 578        mfn = virt_to_mfn(data);
 579        gnttab_grant_foreign_access_ref(
 580                ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
 581        tx->gref = np->grant_tx_ref[id] = ref;
 582        tx->offset = offset;
 583        tx->size = len;
 584        extra = NULL;
 585
 586        tx->flags = 0;
 587        if (skb->ip_summed == CHECKSUM_PARTIAL)
 588                /* local packet? */
 589                tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
 590        else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 591                /* remote but checksummed. */
 592                tx->flags |= XEN_NETTXF_data_validated;
 593
 594        if (skb_shinfo(skb)->gso_size) {
 595                struct xen_netif_extra_info *gso;
 596
 597                gso = (struct xen_netif_extra_info *)
 598                        RING_GET_REQUEST(&np->tx, ++i);
 599
 600                if (extra)
 601                        extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
 602                else
 603                        tx->flags |= XEN_NETTXF_extra_info;
 604
 605                gso->u.gso.size = skb_shinfo(skb)->gso_size;
 606                gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
 607                gso->u.gso.pad = 0;
 608                gso->u.gso.features = 0;
 609
 610                gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
 611                gso->flags = 0;
 612                extra = gso;
 613        }
 614
 615        np->tx.req_prod_pvt = i + 1;
 616
 617        xennet_make_frags(skb, dev, tx);
 618        tx->size = skb->len;
 619
 620        RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
 621        if (notify)
 622                notify_remote_via_irq(np->netdev->irq);
 623
 624        u64_stats_update_begin(&stats->syncp);
 625        stats->tx_bytes += skb->len;
 626        stats->tx_packets++;
 627        u64_stats_update_end(&stats->syncp);
 628
 629        /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
 630        xennet_tx_buf_gc(dev);
 631
 632        if (!netfront_tx_slot_available(np))
 633                netif_stop_queue(dev);
 634
 635        spin_unlock_irqrestore(&np->tx_lock, flags);
 636
 637        return NETDEV_TX_OK;
 638
 639 drop:
 640        dev->stats.tx_dropped++;
 641        dev_kfree_skb(skb);
 642        return NETDEV_TX_OK;
 643}
 644
 645static int xennet_close(struct net_device *dev)
 646{
 647        struct netfront_info *np = netdev_priv(dev);
 648        netif_stop_queue(np->netdev);
 649        napi_disable(&np->napi);
 650        return 0;
 651}
 652
 653static void xennet_move_rx_slot(struct netfront_info *np, struct sk_buff *skb,
 654                                grant_ref_t ref)
 655{
 656        int new = xennet_rxidx(np->rx.req_prod_pvt);
 657
 658        BUG_ON(np->rx_skbs[new]);
 659        np->rx_skbs[new] = skb;
 660        np->grant_rx_ref[new] = ref;
 661        RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new;
 662        RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref;
 663        np->rx.req_prod_pvt++;
 664}
 665
 666static int xennet_get_extras(struct netfront_info *np,
 667                             struct xen_netif_extra_info *extras,
 668                             RING_IDX rp)
 669
 670{
 671        struct xen_netif_extra_info *extra;
 672        struct device *dev = &np->netdev->dev;
 673        RING_IDX cons = np->rx.rsp_cons;
 674        int err = 0;
 675
 676        do {
 677                struct sk_buff *skb;
 678                grant_ref_t ref;
 679
 680                if (unlikely(cons + 1 == rp)) {
 681                        if (net_ratelimit())
 682                                dev_warn(dev, "Missing extra info\n");
 683                        err = -EBADR;
 684                        break;
 685                }
 686
 687                extra = (struct xen_netif_extra_info *)
 688                        RING_GET_RESPONSE(&np->rx, ++cons);
 689
 690                if (unlikely(!extra->type ||
 691                             extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 692                        if (net_ratelimit())
 693                                dev_warn(dev, "Invalid extra type: %d\n",
 694                                        extra->type);
 695                        err = -EINVAL;
 696                } else {
 697                        memcpy(&extras[extra->type - 1], extra,
 698                               sizeof(*extra));
 699                }
 700
 701                skb = xennet_get_rx_skb(np, cons);
 702                ref = xennet_get_rx_ref(np, cons);
 703                xennet_move_rx_slot(np, skb, ref);
 704        } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
 705
 706        np->rx.rsp_cons = cons;
 707        return err;
 708}
 709
 710static int xennet_get_responses(struct netfront_info *np,
 711                                struct netfront_rx_info *rinfo, RING_IDX rp,
 712                                struct sk_buff_head *list)
 713{
 714        struct xen_netif_rx_response *rx = &rinfo->rx;
 715        struct xen_netif_extra_info *extras = rinfo->extras;
 716        struct device *dev = &np->netdev->dev;
 717        RING_IDX cons = np->rx.rsp_cons;
 718        struct sk_buff *skb = xennet_get_rx_skb(np, cons);
 719        grant_ref_t ref = xennet_get_rx_ref(np, cons);
 720        int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
 721        int frags = 1;
 722        int err = 0;
 723        unsigned long ret;
 724
 725        if (rx->flags & XEN_NETRXF_extra_info) {
 726                err = xennet_get_extras(np, extras, rp);
 727                cons = np->rx.rsp_cons;
 728        }
 729
 730        for (;;) {
 731                if (unlikely(rx->status < 0 ||
 732                             rx->offset + rx->status > PAGE_SIZE)) {
 733                        if (net_ratelimit())
 734                                dev_warn(dev, "rx->offset: %x, size: %u\n",
 735                                         rx->offset, rx->status);
 736                        xennet_move_rx_slot(np, skb, ref);
 737                        err = -EINVAL;
 738                        goto next;
 739                }
 740
 741                /*
 742                 * This definitely indicates a bug, either in this driver or in
 743                 * the backend driver. In future this should flag the bad
 744                 * situation to the system controller to reboot the backed.
 745                 */
 746                if (ref == GRANT_INVALID_REF) {
 747                        if (net_ratelimit())
 748                                dev_warn(dev, "Bad rx response id %d.\n",
 749                                         rx->id);
 750                        err = -EINVAL;
 751                        goto next;
 752                }
 753
 754                ret = gnttab_end_foreign_access_ref(ref, 0);
 755                BUG_ON(!ret);
 756
 757                gnttab_release_grant_reference(&np->gref_rx_head, ref);
 758
 759                __skb_queue_tail(list, skb);
 760
 761next:
 762                if (!(rx->flags & XEN_NETRXF_more_data))
 763                        break;
 764
 765                if (cons + frags == rp) {
 766                        if (net_ratelimit())
 767                                dev_warn(dev, "Need more frags\n");
 768                        err = -ENOENT;
 769                        break;
 770                }
 771
 772                rx = RING_GET_RESPONSE(&np->rx, cons + frags);
 773                skb = xennet_get_rx_skb(np, cons + frags);
 774                ref = xennet_get_rx_ref(np, cons + frags);
 775                frags++;
 776        }
 777
 778        if (unlikely(frags > max)) {
 779                if (net_ratelimit())
 780                        dev_warn(dev, "Too many frags\n");
 781                err = -E2BIG;
 782        }
 783
 784        if (unlikely(err))
 785                np->rx.rsp_cons = cons + frags;
 786
 787        return err;
 788}
 789
 790static int xennet_set_skb_gso(struct sk_buff *skb,
 791                              struct xen_netif_extra_info *gso)
 792{
 793        if (!gso->u.gso.size) {
 794                if (net_ratelimit())
 795                        printk(KERN_WARNING "GSO size must not be zero.\n");
 796                return -EINVAL;
 797        }
 798
 799        /* Currently only TCPv4 S.O. is supported. */
 800        if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
 801                if (net_ratelimit())
 802                        printk(KERN_WARNING "Bad GSO type %d.\n", gso->u.gso.type);
 803                return -EINVAL;
 804        }
 805
 806        skb_shinfo(skb)->gso_size = gso->u.gso.size;
 807        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 808
 809        /* Header must be checked, and gso_segs computed. */
 810        skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 811        skb_shinfo(skb)->gso_segs = 0;
 812
 813        return 0;
 814}
 815
 816static RING_IDX xennet_fill_frags(struct netfront_info *np,
 817                                  struct sk_buff *skb,
 818                                  struct sk_buff_head *list)
 819{
 820        struct skb_shared_info *shinfo = skb_shinfo(skb);
 821        int nr_frags = shinfo->nr_frags;
 822        RING_IDX cons = np->rx.rsp_cons;
 823        struct sk_buff *nskb;
 824
 825        while ((nskb = __skb_dequeue(list))) {
 826                struct xen_netif_rx_response *rx =
 827                        RING_GET_RESPONSE(&np->rx, ++cons);
 828                skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
 829
 830                __skb_fill_page_desc(skb, nr_frags,
 831                                     skb_frag_page(nfrag),
 832                                     rx->offset, rx->status);
 833
 834                skb->data_len += rx->status;
 835
 836                skb_shinfo(nskb)->nr_frags = 0;
 837                kfree_skb(nskb);
 838
 839                nr_frags++;
 840        }
 841
 842        shinfo->nr_frags = nr_frags;
 843        return cons;
 844}
 845
 846static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
 847{
 848        struct iphdr *iph;
 849        unsigned char *th;
 850        int err = -EPROTO;
 851        int recalculate_partial_csum = 0;
 852
 853        /*
 854         * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 855         * peers can fail to set NETRXF_csum_blank when sending a GSO
 856         * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 857         * recalculate the partial checksum.
 858         */
 859        if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 860                struct netfront_info *np = netdev_priv(dev);
 861                np->rx_gso_checksum_fixup++;
 862                skb->ip_summed = CHECKSUM_PARTIAL;
 863                recalculate_partial_csum = 1;
 864        }
 865
 866        /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 867        if (skb->ip_summed != CHECKSUM_PARTIAL)
 868                return 0;
 869
 870        if (skb->protocol != htons(ETH_P_IP))
 871                goto out;
 872
 873        iph = (void *)skb->data;
 874        th = skb->data + 4 * iph->ihl;
 875        if (th >= skb_tail_pointer(skb))
 876                goto out;
 877
 878        skb->csum_start = th - skb->head;
 879        switch (iph->protocol) {
 880        case IPPROTO_TCP:
 881                skb->csum_offset = offsetof(struct tcphdr, check);
 882
 883                if (recalculate_partial_csum) {
 884                        struct tcphdr *tcph = (struct tcphdr *)th;
 885                        tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
 886                                                         skb->len - iph->ihl*4,
 887                                                         IPPROTO_TCP, 0);
 888                }
 889                break;
 890        case IPPROTO_UDP:
 891                skb->csum_offset = offsetof(struct udphdr, check);
 892
 893                if (recalculate_partial_csum) {
 894                        struct udphdr *udph = (struct udphdr *)th;
 895                        udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
 896                                                         skb->len - iph->ihl*4,
 897                                                         IPPROTO_UDP, 0);
 898                }
 899                break;
 900        default:
 901                if (net_ratelimit())
 902                        printk(KERN_ERR "Attempting to checksum a non-"
 903                               "TCP/UDP packet, dropping a protocol"
 904                               " %d packet", iph->protocol);
 905                goto out;
 906        }
 907
 908        if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
 909                goto out;
 910
 911        err = 0;
 912
 913out:
 914        return err;
 915}
 916
 917static int handle_incoming_queue(struct net_device *dev,
 918                                 struct sk_buff_head *rxq)
 919{
 920        struct netfront_info *np = netdev_priv(dev);
 921        struct netfront_stats *stats = this_cpu_ptr(np->stats);
 922        int packets_dropped = 0;
 923        struct sk_buff *skb;
 924
 925        while ((skb = __skb_dequeue(rxq)) != NULL) {
 926                int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 927
 928                __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 929
 930                /* Ethernet work: Delayed to here as it peeks the header. */
 931                skb->protocol = eth_type_trans(skb, dev);
 932
 933                if (checksum_setup(dev, skb)) {
 934                        kfree_skb(skb);
 935                        packets_dropped++;
 936                        dev->stats.rx_errors++;
 937                        continue;
 938                }
 939
 940                u64_stats_update_begin(&stats->syncp);
 941                stats->rx_packets++;
 942                stats->rx_bytes += skb->len;
 943                u64_stats_update_end(&stats->syncp);
 944
 945                /* Pass it up. */
 946                netif_receive_skb(skb);
 947        }
 948
 949        return packets_dropped;
 950}
 951
 952static int xennet_poll(struct napi_struct *napi, int budget)
 953{
 954        struct netfront_info *np = container_of(napi, struct netfront_info, napi);
 955        struct net_device *dev = np->netdev;
 956        struct sk_buff *skb;
 957        struct netfront_rx_info rinfo;
 958        struct xen_netif_rx_response *rx = &rinfo.rx;
 959        struct xen_netif_extra_info *extras = rinfo.extras;
 960        RING_IDX i, rp;
 961        int work_done;
 962        struct sk_buff_head rxq;
 963        struct sk_buff_head errq;
 964        struct sk_buff_head tmpq;
 965        unsigned long flags;
 966        int err;
 967
 968        spin_lock(&np->rx_lock);
 969
 970        skb_queue_head_init(&rxq);
 971        skb_queue_head_init(&errq);
 972        skb_queue_head_init(&tmpq);
 973
 974        rp = np->rx.sring->rsp_prod;
 975        rmb(); /* Ensure we see queued responses up to 'rp'. */
 976
 977        i = np->rx.rsp_cons;
 978        work_done = 0;
 979        while ((i != rp) && (work_done < budget)) {
 980                memcpy(rx, RING_GET_RESPONSE(&np->rx, i), sizeof(*rx));
 981                memset(extras, 0, sizeof(rinfo.extras));
 982
 983                err = xennet_get_responses(np, &rinfo, rp, &tmpq);
 984
 985                if (unlikely(err)) {
 986err:
 987                        while ((skb = __skb_dequeue(&tmpq)))
 988                                __skb_queue_tail(&errq, skb);
 989                        dev->stats.rx_errors++;
 990                        i = np->rx.rsp_cons;
 991                        continue;
 992                }
 993
 994                skb = __skb_dequeue(&tmpq);
 995
 996                if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
 997                        struct xen_netif_extra_info *gso;
 998                        gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
 999
1000                        if (unlikely(xennet_set_skb_gso(skb, gso))) {
1001                                __skb_queue_head(&tmpq, skb);
1002                                np->rx.rsp_cons += skb_queue_len(&tmpq);
1003                                goto err;
1004                        }
1005                }
1006
1007                NETFRONT_SKB_CB(skb)->pull_to = rx->status;
1008                if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
1009                        NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
1010
1011                skb_shinfo(skb)->frags[0].page_offset = rx->offset;
1012                skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
1013                skb->data_len = rx->status;
1014
1015                i = xennet_fill_frags(np, skb, &tmpq);
1016
1017                /*
1018                 * Truesize is the actual allocation size, even if the
1019                 * allocation is only partially used.
1020                 */
1021                skb->truesize += PAGE_SIZE * skb_shinfo(skb)->nr_frags;
1022                skb->len += skb->data_len;
1023
1024                if (rx->flags & XEN_NETRXF_csum_blank)
1025                        skb->ip_summed = CHECKSUM_PARTIAL;
1026                else if (rx->flags & XEN_NETRXF_data_validated)
1027                        skb->ip_summed = CHECKSUM_UNNECESSARY;
1028
1029                __skb_queue_tail(&rxq, skb);
1030
1031                np->rx.rsp_cons = ++i;
1032                work_done++;
1033        }
1034
1035        __skb_queue_purge(&errq);
1036
1037        work_done -= handle_incoming_queue(dev, &rxq);
1038
1039        /* If we get a callback with very few responses, reduce fill target. */
1040        /* NB. Note exponential increase, linear decrease. */
1041        if (((np->rx.req_prod_pvt - np->rx.sring->rsp_prod) >
1042             ((3*np->rx_target) / 4)) &&
1043            (--np->rx_target < np->rx_min_target))
1044                np->rx_target = np->rx_min_target;
1045
1046        xennet_alloc_rx_buffers(dev);
1047
1048        if (work_done < budget) {
1049                int more_to_do = 0;
1050
1051                local_irq_save(flags);
1052
1053                RING_FINAL_CHECK_FOR_RESPONSES(&np->rx, more_to_do);
1054                if (!more_to_do)
1055                        __napi_complete(napi);
1056
1057                local_irq_restore(flags);
1058        }
1059
1060        spin_unlock(&np->rx_lock);
1061
1062        return work_done;
1063}
1064
1065static int xennet_change_mtu(struct net_device *dev, int mtu)
1066{
1067        int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN;
1068
1069        if (mtu > max)
1070                return -EINVAL;
1071        dev->mtu = mtu;
1072        return 0;
1073}
1074
1075static struct rtnl_link_stats64 *xennet_get_stats64(struct net_device *dev,
1076                                                    struct rtnl_link_stats64 *tot)
1077{
1078        struct netfront_info *np = netdev_priv(dev);
1079        int cpu;
1080
1081        for_each_possible_cpu(cpu) {
1082                struct netfront_stats *stats = per_cpu_ptr(np->stats, cpu);
1083                u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1084                unsigned int start;
1085
1086                do {
1087                        start = u64_stats_fetch_begin_bh(&stats->syncp);
1088
1089                        rx_packets = stats->rx_packets;
1090                        tx_packets = stats->tx_packets;
1091                        rx_bytes = stats->rx_bytes;
1092                        tx_bytes = stats->tx_bytes;
1093                } while (u64_stats_fetch_retry_bh(&stats->syncp, start));
1094
1095                tot->rx_packets += rx_packets;
1096                tot->tx_packets += tx_packets;
1097                tot->rx_bytes   += rx_bytes;
1098                tot->tx_bytes   += tx_bytes;
1099        }
1100
1101        tot->rx_errors  = dev->stats.rx_errors;
1102        tot->tx_dropped = dev->stats.tx_dropped;
1103
1104        return tot;
1105}
1106
1107static void xennet_release_tx_bufs(struct netfront_info *np)
1108{
1109        struct sk_buff *skb;
1110        int i;
1111
1112        for (i = 0; i < NET_TX_RING_SIZE; i++) {
1113                /* Skip over entries which are actually freelist references */
1114                if (skb_entry_is_link(&np->tx_skbs[i]))
1115                        continue;
1116
1117                skb = np->tx_skbs[i].skb;
1118                gnttab_end_foreign_access_ref(np->grant_tx_ref[i],
1119                                              GNTMAP_readonly);
1120                gnttab_release_grant_reference(&np->gref_tx_head,
1121                                               np->grant_tx_ref[i]);
1122                np->grant_tx_ref[i] = GRANT_INVALID_REF;
1123                add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, i);
1124                dev_kfree_skb_irq(skb);
1125        }
1126}
1127
1128static void xennet_release_rx_bufs(struct netfront_info *np)
1129{
1130        struct mmu_update      *mmu = np->rx_mmu;
1131        struct multicall_entry *mcl = np->rx_mcl;
1132        struct sk_buff_head free_list;
1133        struct sk_buff *skb;
1134        unsigned long mfn;
1135        int xfer = 0, noxfer = 0, unused = 0;
1136        int id, ref;
1137
1138        dev_warn(&np->netdev->dev, "%s: fix me for copying receiver.\n",
1139                         __func__);
1140        return;
1141
1142        skb_queue_head_init(&free_list);
1143
1144        spin_lock_bh(&np->rx_lock);
1145
1146        for (id = 0; id < NET_RX_RING_SIZE; id++) {
1147                ref = np->grant_rx_ref[id];
1148                if (ref == GRANT_INVALID_REF) {
1149                        unused++;
1150                        continue;
1151                }
1152
1153                skb = np->rx_skbs[id];
1154                mfn = gnttab_end_foreign_transfer_ref(ref);
1155                gnttab_release_grant_reference(&np->gref_rx_head, ref);
1156                np->grant_rx_ref[id] = GRANT_INVALID_REF;
1157
1158                if (0 == mfn) {
1159                        skb_shinfo(skb)->nr_frags = 0;
1160                        dev_kfree_skb(skb);
1161                        noxfer++;
1162                        continue;
1163                }
1164
1165                if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1166                        /* Remap the page. */
1167                        const struct page *page =
1168                                skb_frag_page(&skb_shinfo(skb)->frags[0]);
1169                        unsigned long pfn = page_to_pfn(page);
1170                        void *vaddr = page_address(page);
1171
1172                        MULTI_update_va_mapping(mcl, (unsigned long)vaddr,
1173                                                mfn_pte(mfn, PAGE_KERNEL),
1174                                                0);
1175                        mcl++;
1176                        mmu->ptr = ((u64)mfn << PAGE_SHIFT)
1177                                | MMU_MACHPHYS_UPDATE;
1178                        mmu->val = pfn;
1179                        mmu++;
1180
1181                        set_phys_to_machine(pfn, mfn);
1182                }
1183                __skb_queue_tail(&free_list, skb);
1184                xfer++;
1185        }
1186
1187        dev_info(&np->netdev->dev, "%s: %d xfer, %d noxfer, %d unused\n",
1188                 __func__, xfer, noxfer, unused);
1189
1190        if (xfer) {
1191                if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1192                        /* Do all the remapping work and M2P updates. */
1193                        MULTI_mmu_update(mcl, np->rx_mmu, mmu - np->rx_mmu,
1194                                         NULL, DOMID_SELF);
1195                        mcl++;
1196                        HYPERVISOR_multicall(np->rx_mcl, mcl - np->rx_mcl);
1197                }
1198        }
1199
1200        __skb_queue_purge(&free_list);
1201
1202        spin_unlock_bh(&np->rx_lock);
1203}
1204
1205static void xennet_uninit(struct net_device *dev)
1206{
1207        struct netfront_info *np = netdev_priv(dev);
1208        xennet_release_tx_bufs(np);
1209        xennet_release_rx_bufs(np);
1210        gnttab_free_grant_references(np->gref_tx_head);
1211        gnttab_free_grant_references(np->gref_rx_head);
1212}
1213
1214static netdev_features_t xennet_fix_features(struct net_device *dev,
1215        netdev_features_t features)
1216{
1217        struct netfront_info *np = netdev_priv(dev);
1218        int val;
1219
1220        if (features & NETIF_F_SG) {
1221                if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-sg",
1222                                 "%d", &val) < 0)
1223                        val = 0;
1224
1225                if (!val)
1226                        features &= ~NETIF_F_SG;
1227        }
1228
1229        if (features & NETIF_F_TSO) {
1230                if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1231                                 "feature-gso-tcpv4", "%d", &val) < 0)
1232                        val = 0;
1233
1234                if (!val)
1235                        features &= ~NETIF_F_TSO;
1236        }
1237
1238        return features;
1239}
1240
1241static int xennet_set_features(struct net_device *dev,
1242        netdev_features_t features)
1243{
1244        if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1245                netdev_info(dev, "Reducing MTU because no SG offload");
1246                dev->mtu = ETH_DATA_LEN;
1247        }
1248
1249        return 0;
1250}
1251
1252static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1253{
1254        struct net_device *dev = dev_id;
1255        struct netfront_info *np = netdev_priv(dev);
1256        unsigned long flags;
1257
1258        spin_lock_irqsave(&np->tx_lock, flags);
1259
1260        if (likely(netif_carrier_ok(dev))) {
1261                xennet_tx_buf_gc(dev);
1262                /* Under tx_lock: protects access to rx shared-ring indexes. */
1263                if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
1264                        napi_schedule(&np->napi);
1265        }
1266
1267        spin_unlock_irqrestore(&np->tx_lock, flags);
1268
1269        return IRQ_HANDLED;
1270}
1271
1272#ifdef CONFIG_NET_POLL_CONTROLLER
1273static void xennet_poll_controller(struct net_device *dev)
1274{
1275        xennet_interrupt(0, dev);
1276}
1277#endif
1278
1279static const struct net_device_ops xennet_netdev_ops = {
1280        .ndo_open            = xennet_open,
1281        .ndo_uninit          = xennet_uninit,
1282        .ndo_stop            = xennet_close,
1283        .ndo_start_xmit      = xennet_start_xmit,
1284        .ndo_change_mtu      = xennet_change_mtu,
1285        .ndo_get_stats64     = xennet_get_stats64,
1286        .ndo_set_mac_address = eth_mac_addr,
1287        .ndo_validate_addr   = eth_validate_addr,
1288        .ndo_fix_features    = xennet_fix_features,
1289        .ndo_set_features    = xennet_set_features,
1290#ifdef CONFIG_NET_POLL_CONTROLLER
1291        .ndo_poll_controller = xennet_poll_controller,
1292#endif
1293};
1294
1295static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev)
1296{
1297        int i, err;
1298        struct net_device *netdev;
1299        struct netfront_info *np;
1300
1301        netdev = alloc_etherdev(sizeof(struct netfront_info));
1302        if (!netdev)
1303                return ERR_PTR(-ENOMEM);
1304
1305        np                   = netdev_priv(netdev);
1306        np->xbdev            = dev;
1307
1308        spin_lock_init(&np->tx_lock);
1309        spin_lock_init(&np->rx_lock);
1310
1311        skb_queue_head_init(&np->rx_batch);
1312        np->rx_target     = RX_DFL_MIN_TARGET;
1313        np->rx_min_target = RX_DFL_MIN_TARGET;
1314        np->rx_max_target = RX_MAX_TARGET;
1315
1316        init_timer(&np->rx_refill_timer);
1317        np->rx_refill_timer.data = (unsigned long)netdev;
1318        np->rx_refill_timer.function = rx_refill_timeout;
1319
1320        err = -ENOMEM;
1321        np->stats = alloc_percpu(struct netfront_stats);
1322        if (np->stats == NULL)
1323                goto exit;
1324
1325        /* Initialise tx_skbs as a free chain containing every entry. */
1326        np->tx_skb_freelist = 0;
1327        for (i = 0; i < NET_TX_RING_SIZE; i++) {
1328                skb_entry_set_link(&np->tx_skbs[i], i+1);
1329                np->grant_tx_ref[i] = GRANT_INVALID_REF;
1330        }
1331
1332        /* Clear out rx_skbs */
1333        for (i = 0; i < NET_RX_RING_SIZE; i++) {
1334                np->rx_skbs[i] = NULL;
1335                np->grant_rx_ref[i] = GRANT_INVALID_REF;
1336        }
1337
1338        /* A grant for every tx ring slot */
1339        if (gnttab_alloc_grant_references(TX_MAX_TARGET,
1340                                          &np->gref_tx_head) < 0) {
1341                printk(KERN_ALERT "#### netfront can't alloc tx grant refs\n");
1342                err = -ENOMEM;
1343                goto exit_free_stats;
1344        }
1345        /* A grant for every rx ring slot */
1346        if (gnttab_alloc_grant_references(RX_MAX_TARGET,
1347                                          &np->gref_rx_head) < 0) {
1348                printk(KERN_ALERT "#### netfront can't alloc rx grant refs\n");
1349                err = -ENOMEM;
1350                goto exit_free_tx;
1351        }
1352
1353        netdev->netdev_ops      = &xennet_netdev_ops;
1354
1355        netif_napi_add(netdev, &np->napi, xennet_poll, 64);
1356        netdev->features        = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1357                                  NETIF_F_GSO_ROBUST;
1358        netdev->hw_features     = NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO;
1359
1360        /*
1361         * Assume that all hw features are available for now. This set
1362         * will be adjusted by the call to netdev_update_features() in
1363         * xennet_connect() which is the earliest point where we can
1364         * negotiate with the backend regarding supported features.
1365         */
1366        netdev->features |= netdev->hw_features;
1367
1368        SET_ETHTOOL_OPS(netdev, &xennet_ethtool_ops);
1369        SET_NETDEV_DEV(netdev, &dev->dev);
1370
1371        np->netdev = netdev;
1372
1373        netif_carrier_off(netdev);
1374
1375        return netdev;
1376
1377 exit_free_tx:
1378        gnttab_free_grant_references(np->gref_tx_head);
1379 exit_free_stats:
1380        free_percpu(np->stats);
1381 exit:
1382        free_netdev(netdev);
1383        return ERR_PTR(err);
1384}
1385
1386/**
1387 * Entry point to this code when a new device is created.  Allocate the basic
1388 * structures and the ring buffers for communication with the backend, and
1389 * inform the backend of the appropriate details for those.
1390 */
1391static int __devinit netfront_probe(struct xenbus_device *dev,
1392                                    const struct xenbus_device_id *id)
1393{
1394        int err;
1395        struct net_device *netdev;
1396        struct netfront_info *info;
1397
1398        netdev = xennet_create_dev(dev);
1399        if (IS_ERR(netdev)) {
1400                err = PTR_ERR(netdev);
1401                xenbus_dev_fatal(dev, err, "creating netdev");
1402                return err;
1403        }
1404
1405        info = netdev_priv(netdev);
1406        dev_set_drvdata(&dev->dev, info);
1407
1408        err = register_netdev(info->netdev);
1409        if (err) {
1410                printk(KERN_WARNING "%s: register_netdev err=%d\n",
1411                       __func__, err);
1412                goto fail;
1413        }
1414
1415        err = xennet_sysfs_addif(info->netdev);
1416        if (err) {
1417                unregister_netdev(info->netdev);
1418                printk(KERN_WARNING "%s: add sysfs failed err=%d\n",
1419                       __func__, err);
1420                goto fail;
1421        }
1422
1423        return 0;
1424
1425 fail:
1426        free_netdev(netdev);
1427        dev_set_drvdata(&dev->dev, NULL);
1428        return err;
1429}
1430
1431static void xennet_end_access(int ref, void *page)
1432{
1433        /* This frees the page as a side-effect */
1434        if (ref != GRANT_INVALID_REF)
1435                gnttab_end_foreign_access(ref, 0, (unsigned long)page);
1436}
1437
1438static void xennet_disconnect_backend(struct netfront_info *info)
1439{
1440        /* Stop old i/f to prevent errors whilst we rebuild the state. */
1441        spin_lock_bh(&info->rx_lock);
1442        spin_lock_irq(&info->tx_lock);
1443        netif_carrier_off(info->netdev);
1444        spin_unlock_irq(&info->tx_lock);
1445        spin_unlock_bh(&info->rx_lock);
1446
1447        if (info->netdev->irq)
1448                unbind_from_irqhandler(info->netdev->irq, info->netdev);
1449        info->evtchn = info->netdev->irq = 0;
1450
1451        /* End access and free the pages */
1452        xennet_end_access(info->tx_ring_ref, info->tx.sring);
1453        xennet_end_access(info->rx_ring_ref, info->rx.sring);
1454
1455        info->tx_ring_ref = GRANT_INVALID_REF;
1456        info->rx_ring_ref = GRANT_INVALID_REF;
1457        info->tx.sring = NULL;
1458        info->rx.sring = NULL;
1459}
1460
1461/**
1462 * We are reconnecting to the backend, due to a suspend/resume, or a backend
1463 * driver restart.  We tear down our netif structure and recreate it, but
1464 * leave the device-layer structures intact so that this is transparent to the
1465 * rest of the kernel.
1466 */
1467static int netfront_resume(struct xenbus_device *dev)
1468{
1469        struct netfront_info *info = dev_get_drvdata(&dev->dev);
1470
1471        dev_dbg(&dev->dev, "%s\n", dev->nodename);
1472
1473        xennet_disconnect_backend(info);
1474        return 0;
1475}
1476
1477static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1478{
1479        char *s, *e, *macstr;
1480        int i;
1481
1482        macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1483        if (IS_ERR(macstr))
1484                return PTR_ERR(macstr);
1485
1486        for (i = 0; i < ETH_ALEN; i++) {
1487                mac[i] = simple_strtoul(s, &e, 16);
1488                if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1489                        kfree(macstr);
1490                        return -ENOENT;
1491                }
1492                s = e+1;
1493        }
1494
1495        kfree(macstr);
1496        return 0;
1497}
1498
1499static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
1500{
1501        struct xen_netif_tx_sring *txs;
1502        struct xen_netif_rx_sring *rxs;
1503        int err;
1504        struct net_device *netdev = info->netdev;
1505
1506        info->tx_ring_ref = GRANT_INVALID_REF;
1507        info->rx_ring_ref = GRANT_INVALID_REF;
1508        info->rx.sring = NULL;
1509        info->tx.sring = NULL;
1510        netdev->irq = 0;
1511
1512        err = xen_net_read_mac(dev, netdev->dev_addr);
1513        if (err) {
1514                xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
1515                goto fail;
1516        }
1517
1518        txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1519        if (!txs) {
1520                err = -ENOMEM;
1521                xenbus_dev_fatal(dev, err, "allocating tx ring page");
1522                goto fail;
1523        }
1524        SHARED_RING_INIT(txs);
1525        FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);
1526
1527        err = xenbus_grant_ring(dev, virt_to_mfn(txs));
1528        if (err < 0) {
1529                free_page((unsigned long)txs);
1530                goto fail;
1531        }
1532
1533        info->tx_ring_ref = err;
1534        rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1535        if (!rxs) {
1536                err = -ENOMEM;
1537                xenbus_dev_fatal(dev, err, "allocating rx ring page");
1538                goto fail;
1539        }
1540        SHARED_RING_INIT(rxs);
1541        FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);
1542
1543        err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
1544        if (err < 0) {
1545                free_page((unsigned long)rxs);
1546                goto fail;
1547        }
1548        info->rx_ring_ref = err;
1549
1550        err = xenbus_alloc_evtchn(dev, &info->evtchn);
1551        if (err)
1552                goto fail;
1553
1554        err = bind_evtchn_to_irqhandler(info->evtchn, xennet_interrupt,
1555                                        0, netdev->name, netdev);
1556        if (err < 0)
1557                goto fail;
1558        netdev->irq = err;
1559        return 0;
1560
1561 fail:
1562        return err;
1563}
1564
1565/* Common code used when first setting up, and when resuming. */
1566static int talk_to_netback(struct xenbus_device *dev,
1567                           struct netfront_info *info)
1568{
1569        const char *message;
1570        struct xenbus_transaction xbt;
1571        int err;
1572
1573        /* Create shared ring, alloc event channel. */
1574        err = setup_netfront(dev, info);
1575        if (err)
1576                goto out;
1577
1578again:
1579        err = xenbus_transaction_start(&xbt);
1580        if (err) {
1581                xenbus_dev_fatal(dev, err, "starting transaction");
1582                goto destroy_ring;
1583        }
1584
1585        err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref", "%u",
1586                            info->tx_ring_ref);
1587        if (err) {
1588                message = "writing tx ring-ref";
1589                goto abort_transaction;
1590        }
1591        err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref", "%u",
1592                            info->rx_ring_ref);
1593        if (err) {
1594                message = "writing rx ring-ref";
1595                goto abort_transaction;
1596        }
1597        err = xenbus_printf(xbt, dev->nodename,
1598                            "event-channel", "%u", info->evtchn);
1599        if (err) {
1600                message = "writing event-channel";
1601                goto abort_transaction;
1602        }
1603
1604        err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
1605                            1);
1606        if (err) {
1607                message = "writing request-rx-copy";
1608                goto abort_transaction;
1609        }
1610
1611        err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
1612        if (err) {
1613                message = "writing feature-rx-notify";
1614                goto abort_transaction;
1615        }
1616
1617        err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
1618        if (err) {
1619                message = "writing feature-sg";
1620                goto abort_transaction;
1621        }
1622
1623        err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
1624        if (err) {
1625                message = "writing feature-gso-tcpv4";
1626                goto abort_transaction;
1627        }
1628
1629        err = xenbus_transaction_end(xbt, 0);
1630        if (err) {
1631                if (err == -EAGAIN)
1632                        goto again;
1633                xenbus_dev_fatal(dev, err, "completing transaction");
1634                goto destroy_ring;
1635        }
1636
1637        return 0;
1638
1639 abort_transaction:
1640        xenbus_transaction_end(xbt, 1);
1641        xenbus_dev_fatal(dev, err, "%s", message);
1642 destroy_ring:
1643        xennet_disconnect_backend(info);
1644 out:
1645        return err;
1646}
1647
1648static int xennet_connect(struct net_device *dev)
1649{
1650        struct netfront_info *np = netdev_priv(dev);
1651        int i, requeue_idx, err;
1652        struct sk_buff *skb;
1653        grant_ref_t ref;
1654        struct xen_netif_rx_request *req;
1655        unsigned int feature_rx_copy;
1656
1657        err = xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1658                           "feature-rx-copy", "%u", &feature_rx_copy);
1659        if (err != 1)
1660                feature_rx_copy = 0;
1661
1662        if (!feature_rx_copy) {
1663                dev_info(&dev->dev,
1664                         "backend does not support copying receive path\n");
1665                return -ENODEV;
1666        }
1667
1668        err = talk_to_netback(np->xbdev, np);
1669        if (err)
1670                return err;
1671
1672        rtnl_lock();
1673        netdev_update_features(dev);
1674        rtnl_unlock();
1675
1676        spin_lock_bh(&np->rx_lock);
1677        spin_lock_irq(&np->tx_lock);
1678
1679        /* Step 1: Discard all pending TX packet fragments. */
1680        xennet_release_tx_bufs(np);
1681
1682        /* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */
1683        for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) {
1684                skb_frag_t *frag;
1685                const struct page *page;
1686                if (!np->rx_skbs[i])
1687                        continue;
1688
1689                skb = np->rx_skbs[requeue_idx] = xennet_get_rx_skb(np, i);
1690                ref = np->grant_rx_ref[requeue_idx] = xennet_get_rx_ref(np, i);
1691                req = RING_GET_REQUEST(&np->rx, requeue_idx);
1692
1693                frag = &skb_shinfo(skb)->frags[0];
1694                page = skb_frag_page(frag);
1695                gnttab_grant_foreign_access_ref(
1696                        ref, np->xbdev->otherend_id,
1697                        pfn_to_mfn(page_to_pfn(page)),
1698                        0);
1699                req->gref = ref;
1700                req->id   = requeue_idx;
1701
1702                requeue_idx++;
1703        }
1704
1705        np->rx.req_prod_pvt = requeue_idx;
1706
1707        /*
1708         * Step 3: All public and private state should now be sane.  Get
1709         * ready to start sending and receiving packets and give the driver
1710         * domain a kick because we've probably just requeued some
1711         * packets.
1712         */
1713        netif_carrier_on(np->netdev);
1714        notify_remote_via_irq(np->netdev->irq);
1715        xennet_tx_buf_gc(dev);
1716        xennet_alloc_rx_buffers(dev);
1717
1718        spin_unlock_irq(&np->tx_lock);
1719        spin_unlock_bh(&np->rx_lock);
1720
1721        return 0;
1722}
1723
1724/**
1725 * Callback received when the backend's state changes.
1726 */
1727static void netback_changed(struct xenbus_device *dev,
1728                            enum xenbus_state backend_state)
1729{
1730        struct netfront_info *np = dev_get_drvdata(&dev->dev);
1731        struct net_device *netdev = np->netdev;
1732
1733        dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
1734
1735        switch (backend_state) {
1736        case XenbusStateInitialising:
1737        case XenbusStateInitialised:
1738        case XenbusStateReconfiguring:
1739        case XenbusStateReconfigured:
1740        case XenbusStateUnknown:
1741        case XenbusStateClosed:
1742                break;
1743
1744        case XenbusStateInitWait:
1745                if (dev->state != XenbusStateInitialising)
1746                        break;
1747                if (xennet_connect(netdev) != 0)
1748                        break;
1749                xenbus_switch_state(dev, XenbusStateConnected);
1750                break;
1751
1752        case XenbusStateConnected:
1753                netdev_notify_peers(netdev);
1754                break;
1755
1756        case XenbusStateClosing:
1757                xenbus_frontend_closed(dev);
1758                break;
1759        }
1760}
1761
1762static const struct xennet_stat {
1763        char name[ETH_GSTRING_LEN];
1764        u16 offset;
1765} xennet_stats[] = {
1766        {
1767                "rx_gso_checksum_fixup",
1768                offsetof(struct netfront_info, rx_gso_checksum_fixup)
1769        },
1770};
1771
1772static int xennet_get_sset_count(struct net_device *dev, int string_set)
1773{
1774        switch (string_set) {
1775        case ETH_SS_STATS:
1776                return ARRAY_SIZE(xennet_stats);
1777        default:
1778                return -EINVAL;
1779        }
1780}
1781
1782static void xennet_get_ethtool_stats(struct net_device *dev,
1783                                     struct ethtool_stats *stats, u64 * data)
1784{
1785        void *np = netdev_priv(dev);
1786        int i;
1787
1788        for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
1789                data[i] = *(unsigned long *)(np + xennet_stats[i].offset);
1790}
1791
1792static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
1793{
1794        int i;
1795
1796        switch (stringset) {
1797        case ETH_SS_STATS:
1798                for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
1799                        memcpy(data + i * ETH_GSTRING_LEN,
1800                               xennet_stats[i].name, ETH_GSTRING_LEN);
1801                break;
1802        }
1803}
1804
1805static const struct ethtool_ops xennet_ethtool_ops =
1806{
1807        .get_link = ethtool_op_get_link,
1808
1809        .get_sset_count = xennet_get_sset_count,
1810        .get_ethtool_stats = xennet_get_ethtool_stats,
1811        .get_strings = xennet_get_strings,
1812};
1813
1814#ifdef CONFIG_SYSFS
1815static ssize_t show_rxbuf_min(struct device *dev,
1816                              struct device_attribute *attr, char *buf)
1817{
1818        struct net_device *netdev = to_net_dev(dev);
1819        struct netfront_info *info = netdev_priv(netdev);
1820
1821        return sprintf(buf, "%u\n", info->rx_min_target);
1822}
1823
1824static ssize_t store_rxbuf_min(struct device *dev,
1825                               struct device_attribute *attr,
1826                               const char *buf, size_t len)
1827{
1828        struct net_device *netdev = to_net_dev(dev);
1829        struct netfront_info *np = netdev_priv(netdev);
1830        char *endp;
1831        unsigned long target;
1832
1833        if (!capable(CAP_NET_ADMIN))
1834                return -EPERM;
1835
1836        target = simple_strtoul(buf, &endp, 0);
1837        if (endp == buf)
1838                return -EBADMSG;
1839
1840        if (target < RX_MIN_TARGET)
1841                target = RX_MIN_TARGET;
1842        if (target > RX_MAX_TARGET)
1843                target = RX_MAX_TARGET;
1844
1845        spin_lock_bh(&np->rx_lock);
1846        if (target > np->rx_max_target)
1847                np->rx_max_target = target;
1848        np->rx_min_target = target;
1849        if (target > np->rx_target)
1850                np->rx_target = target;
1851
1852        xennet_alloc_rx_buffers(netdev);
1853
1854        spin_unlock_bh(&np->rx_lock);
1855        return len;
1856}
1857
1858static ssize_t show_rxbuf_max(struct device *dev,
1859                              struct device_attribute *attr, char *buf)
1860{
1861        struct net_device *netdev = to_net_dev(dev);
1862        struct netfront_info *info = netdev_priv(netdev);
1863
1864        return sprintf(buf, "%u\n", info->rx_max_target);
1865}
1866
1867static ssize_t store_rxbuf_max(struct device *dev,
1868                               struct device_attribute *attr,
1869                               const char *buf, size_t len)
1870{
1871        struct net_device *netdev = to_net_dev(dev);
1872        struct netfront_info *np = netdev_priv(netdev);
1873        char *endp;
1874        unsigned long target;
1875
1876        if (!capable(CAP_NET_ADMIN))
1877                return -EPERM;
1878
1879        target = simple_strtoul(buf, &endp, 0);
1880        if (endp == buf)
1881                return -EBADMSG;
1882
1883        if (target < RX_MIN_TARGET)
1884                target = RX_MIN_TARGET;
1885        if (target > RX_MAX_TARGET)
1886                target = RX_MAX_TARGET;
1887
1888        spin_lock_bh(&np->rx_lock);
1889        if (target < np->rx_min_target)
1890                np->rx_min_target = target;
1891        np->rx_max_target = target;
1892        if (target < np->rx_target)
1893                np->rx_target = target;
1894
1895        xennet_alloc_rx_buffers(netdev);
1896
1897        spin_unlock_bh(&np->rx_lock);
1898        return len;
1899}
1900
1901static ssize_t show_rxbuf_cur(struct device *dev,
1902                              struct device_attribute *attr, char *buf)
1903{
1904        struct net_device *netdev = to_net_dev(dev);
1905        struct netfront_info *info = netdev_priv(netdev);
1906
1907        return sprintf(buf, "%u\n", info->rx_target);
1908}
1909
1910static struct device_attribute xennet_attrs[] = {
1911        __ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf_min, store_rxbuf_min),
1912        __ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf_max, store_rxbuf_max),
1913        __ATTR(rxbuf_cur, S_IRUGO, show_rxbuf_cur, NULL),
1914};
1915
1916static int xennet_sysfs_addif(struct net_device *netdev)
1917{
1918        int i;
1919        int err;
1920
1921        for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) {
1922                err = device_create_file(&netdev->dev,
1923                                           &xennet_attrs[i]);
1924                if (err)
1925                        goto fail;
1926        }
1927        return 0;
1928
1929 fail:
1930        while (--i >= 0)
1931                device_remove_file(&netdev->dev, &xennet_attrs[i]);
1932        return err;
1933}
1934
1935static void xennet_sysfs_delif(struct net_device *netdev)
1936{
1937        int i;
1938
1939        for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++)
1940                device_remove_file(&netdev->dev, &xennet_attrs[i]);
1941}
1942
1943#endif /* CONFIG_SYSFS */
1944
1945static const struct xenbus_device_id netfront_ids[] = {
1946        { "vif" },
1947        { "" }
1948};
1949
1950
1951static int __devexit xennet_remove(struct xenbus_device *dev)
1952{
1953        struct netfront_info *info = dev_get_drvdata(&dev->dev);
1954
1955        dev_dbg(&dev->dev, "%s\n", dev->nodename);
1956
1957        xennet_disconnect_backend(info);
1958
1959        xennet_sysfs_delif(info->netdev);
1960
1961        unregister_netdev(info->netdev);
1962
1963        del_timer_sync(&info->rx_refill_timer);
1964
1965        free_percpu(info->stats);
1966
1967        free_netdev(info->netdev);
1968
1969        return 0;
1970}
1971
1972static DEFINE_XENBUS_DRIVER(netfront, ,
1973        .probe = netfront_probe,
1974        .remove = __devexit_p(xennet_remove),
1975        .resume = netfront_resume,
1976        .otherend_changed = netback_changed,
1977);
1978
1979static int __init netif_init(void)
1980{
1981        if (!xen_domain())
1982                return -ENODEV;
1983
1984        if (xen_hvm_domain() && !xen_platform_pci_unplug)
1985                return -ENODEV;
1986
1987        printk(KERN_INFO "Initialising Xen virtual ethernet driver.\n");
1988
1989        return xenbus_register_frontend(&netfront_driver);
1990}
1991module_init(netif_init);
1992
1993
1994static void __exit netif_exit(void)
1995{
1996        xenbus_unregister_driver(&netfront_driver);
1997}
1998module_exit(netif_exit);
1999
2000MODULE_DESCRIPTION("Xen virtual network device frontend");
2001MODULE_LICENSE("GPL");
2002MODULE_ALIAS("xen:vif");
2003MODULE_ALIAS("xennet");
2004
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